Project Summary/Abstract The ultimate goal of the proposed project is to evaluate and commercialize a combination of proprietary magnet assemblies and magnetic nanoparticles that has been shown in small animal and cadaveric large animal and human studies to improve delivery of medications to the inner ear. Studies using the system (which uses magnetic forces to inject drug-eluting magnetic nano-particles into the inner ear) have successfully reduced the degree of hearing loss and tinnitus in rats due to acoustic trauma, and have conferred hearing protection against chemotherapy regimens in mice. The amount of drug reaching the inner ear was increased ten-fold and the drug distribution uniformity was increased three-fold, as compared to the current standard of trans-tympanic injection into the middle ear. Our strategy is to demonstrate the utility of the magnetic injection system as a platform technology addressing the $4 billion hearing market, starting with a compelling orphan indication (sudden sensorineural hearing loss) that is currently without a cure and is considered an otologic emergency. Subsequently, we shall address other cochlear conditions such as tinnitus and protection of hearing during chemotherapy regimens that are also not adequately addressed by the current standards-of-care. The FDA recommends testing in at least two mammalian species, the second of which should be a non-rodent mammal before entry into human trials. Based on successful Phase 1 results in rodents, and on reviewer suggestions, in Phase 2 we shall conduct large animal testing in sheep. Sheep are recognized to have a similar ear anatomy and hearing as compared to humans, and a common animal model submitted to the FDA. We aim to: Aim 1: Select sheep noise trauma conditions based on previously published data. Aim 2: Select dose and show therapeutic effect for noise-trauma-induced hearing loss in sheep. Aim 3: Conduct a detailed safety and toxicology study in healthy (no noise trauma) sheep. We anticipate that small (Phase 1) and large animal (Phase 2) safety and therapeutic effect data in animals will support an IND (Investigational New Drug) filing to the FDA. Approval of an IND by the FDA is required to allow entry into human clinical trials.